Lens driving device, camera device and electronic apparatus

ABSTRACT

A lens driving device includes: a lens carrier for fixing a lens barrel to the inside thereof; a driving Unit for moving the lens carrier along the optical axis direction of the lens barrel; and an upper leaf spring and a lower leaf spring attached to the lens carrier in a manner that a surface of the each upper leaf spring and lower leaf spring is oriented orthogonal to the optical axis direction at an upper part and a lower part of the lens carrier and so that the lens carrier is supported in a manner to move freely in the optical axis direction of the lens barrel; wherein the lens carrier has an opening through which the lens barrel can be inserted from the direction intersecting the optical axis direction of the lens barrel.

TECHNICAL FIELD

This invention relates to a lens driving device, a camera device and an electronic apparatus.

BACKGROUND ART

Electronic apparatuses such as cellular phones and smart phones are equipped with miniaturized cameras. The miniaturized camera of this type is an automatic focusing type. The miniaturized camera of this automatic focusing type includes a lens driving device for actuating the lens barrel to move.

The Japanese Unexamined Patent Application Publication No. 2010-134409A discloses a lens driving device in which a lens barrel is fixed inside a lens carrier and the lens carrier is moved along the optical axis direction of the lens barrel thereby adjusting the focus.

SUMMARY

In the above prior art, a main body is formed with an opening portion which opens toward the optical axis direction of the lens barrel through which opening portion the lens barrel is inserted along the optical axis direction and thereafter the lens barrel is fixed to the lens carrier. The lens barrel is slid and fit into the lens carrier without an aid of threads at the portion between the lens barrel and the lens carrier. Therefore, the above Japanese Unexamined Patent Application Publication No. 2010-134409A explains that the lens driving device can be miniaturized since both the lens barrel and the lens carrier do not need to have any threads.

However, since the lens barrel has to be inserted into the lens carrier in a sliding manner from the optical axis direction, there needs to have a sliding wall for the lens barrel to be slid inside the lens carrier. Therefore, the lens carrier cannot be miniaturized, and it hinders the miniaturization of the lens driving device.

The present invention aims to solve the problem of the prior art, and to provide a lens driving device, camera device and an electronic apparatus which are able to be miniaturized.

In one aspect of the present invention, a lens driving device is provided. The lens driving device includes: a lens carrier for fixing a lens barrel to the inside thereof; a driving unit for moving the lens carrier along the optical axis direction of the lens barrel; and an upper leaf spring and a lower leaf spring attached to the lens carrier in a manner that a surface of the each upper leaf spring and lower leaf spring is oriented orthogonal to the optical axis direction at an upper part and a lower part of the lens carrier and so that the lens carrier is supported in a manner to move freely in the optical axis direction of the lens barrel; wherein the lens carrier has an opening through which the lens barrel can be inserted from the direction intersecting the optical axis direction of the lens barrel.

Preferably, the driving unit has coils and magnets; wherein the coils are arranged on the both sides of the lens carrier around the optical axis of the lens barrel.

Preferably, the coils on the both sides of the lens carrier are electrically connected in parallel with respect to each other.

Preferably, conducting members for supplying electricity to the coils are provided on one side of the lens carrier in the optical axis direction of the lens barrel.

Preferably, terminals connected to the conducting members are arranged on one side apart from the center of the lens barrel.

Preferably, the lens driving device further includes a yoke for supporting the magnets; wherein the yoke surrounds the lens carrier except the opening thereof.

Preferably, the magnets are fixed to the both sides of the yoke around the optical axis of the lens barrel in a manner to face toward the coils.

Preferably, the magnets are arranged facing toward each other in a manner that their magnetic poles of facing sides thereof are different.

Preferably, the lens carrier includes a main body made of resin and a reinforcement member made of metal; and wherein the main body is reinforced with respect to a direction intersecting the optical axis direction of the lens barrel by means of the reinforcement member.

Preferably, an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.

In another aspect of the present invention, a camera device including a lens driving device and a photo detecting sensor receiving light passed through the lens barrel is provided.

Further according to another aspect of the present invention, an electronic device is equipped with the camera apparatus.

According to the present invention, since the lens carrier has the opening through which the lens barrel can be inserted from the direction intersecting the optical axis of the lens barrel, the lens carrier can be miniaturized, thus the lens driving device, the camera device and the electronic apparatus can also be miniaturized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exploded perspective view of a lens driving device according to an embodiment of the present invention.

FIG. 2 shows a perspective view of the lens driving device according the embodiment of the present invention.

FIG. 3 shows the lens driving device according to the embodiment of the present invention and shows a perspective view of the lens driving device of FIG. 2 in a state a cover member is removed.

FIG. 4 shows the lens driving device according to the embodiment of the present invention and shows a sectional perspective view cut by a plane which includes the optical axis of the lens barrel and expands in the vertical direction and a right-and-left direction.

FIG. 5 shows the lens driving device according to the embodiment of the present invention and shows a sectional perspective view cut by a plane which includes the optical axis of the lens barrel and expands in the vertical direction and a front-and-back direction.

FIG. 6 shows the lens carrier used for the lens driving device according to the embodiment of the present invention.

FIG. 7 shows a perspective view of upper leaf springs in the lens driving device according to the embodiment of the present invention.

FIG. 8 shows a perspective view of the lower leaf springs in the lens driving device viewing from the lower side according to the embodiment of the present invention.

EXEMPLARY EMBODIMENT OF THE INVENTION

An embodiment of the present invention will be described hereinafter with reference to the drawings.

FIG. 1 shows an exploded perspective view of a lens driving device according to an embodiment of the present invention. The lens driving device 10 includes an upper member 12, a cover member 14, a lower member 16, a yoke 18, a reinforcement member 20, a main body 22 of the lens carrier, magnets 24, coils 26, upper leaf springs 28, lower leaf springs 30 and terminals 32.

In the following description, as shown in FIG. 1, one direction along the optical axis direction of the lens barrel 40 described later is referred to as “upward” direction while the opposing direction thereto is referred to as “downward” direction. The one direction orthogonal to the optical axis direction of the lens barrel 40 is referred to as “forward” direction while the opposing direction thereto is referred to as “backward” direction. Further, the one direction orthogonal to the upward-and-downward direction and the forward-and-backward direction is referred to as “leftward” direction while the opposing direction thereto is referred to as “rightward” direction.

The upper member 12 has a top wall 12 a and sidewalls 12 b extending downwardly from the right and left ends and the back end of the top wall 12 a. The lateral side walls 12 b are formed inside thereof with inclined parts 12 c for positioning a prism 36 which is described later.

The cover member 14 is formed with a light entrance window 14 a through which the light enters. The lower member 16 is formed as a rectangular parallelepiped shape and is formed at inside thereof with a light exit window 16 a through which the light exits. The lower member 16 is installed with an IR filter and an optical sensor when the camera device mentioned below is assembled.

The yoke 18 is formed as a U-shaped member including three walls, i.e. a left side swill 18 a, a right side wall 18 b and a back side wall 18 c which surround an internal space except the front portion. As for the front portion, the distal ends of the left side wall 18 a and the right side wall 18 b are bent in a manner to be directed toward each other.

A lens driving device housing 34 is composed of the upper member 12, the cover member 14, the lower member 16 and the yoke 18. That is, the lens driving device housing 34 is assembled by the following manner: fitting the upper member 12 into the yoke 18 so that the outer faces of the side walls 12 b of the upper member 12 are fit inside the internal faces of the left side wall 18 a, right side wall 18 b and back side wall 18 c; fitting the lower member 16 into the yoke 18 so that the outer faces of the lower member 16 are fit inside the internal faces of the left side wall 18 a, right side wall 18 b and back side wall 18 c; and fitting the cover member 14 into the upper member 12, the lower member 16 and the yoke 18. Thus the lens driving device housing 34 forms a parallelepiped shape having a hollow space inside thereof so as to block up the front face of the yoke 18.

As shown in FIGS. 2 to 5, the prism 36 is fixed inside the upper member 12. The prism 36 is an optical component which forms an optical system bending the optical axis direction and has a triangle cross section. The prism 36 is arranged so that the front face thereof is fit behind the light entrance window 14 a of the center member 14, the both lateral sides of an inclined back surface thereof abut along the inclined parts 12 c of the upper member 12 and the lower face directs downward. Thus, the prism receives the light from the front face and thereafter reflects the light at the inclined back surface toward the downward direction.

As best shown in FIG. 6, the reinforcement member 20 and the main body 22 of the lens carrier are assembled together to form the lens carrier 38. The main body 22 of the lens carrier is formed of resin and has a bottom portion 22 a having a rectangular frame shape and coil mounting portions 22 b extending upwardly from the lateral ends of the bottom portion 22 a. The reinforcement member 20 is formed of a metal such as stainless steel and is formed as a rectangular frame shape. The reinforcement member 20 reinforces the main body 22 of the lens carrier by means of the lateral sides thereof being fixed to the upper ends of the coil mounting portions 22 b of the main body 22 of the lens carrier from the inside thereof.

The lens carrier 38, as shown in FIGS. 3 and 5, has an opening 38 a through which the lens barrel 40 can be inserted. The opening 38 a is formed so as to be surrounded by the reinforcement member 20, the bottom portion 22 a of the main body 22 of the lens carrier and the coil mounting portions 22 b. The opening 38 a opens toward the front direction. During the assembly process, as shown in FIG. 3, the lens barrel 40 is inserted through the opening 38 a from the front side into the lens carrier 38 previous to the assembly of the cover member 14.

The main body 22 of the lens carrier is formed with abutment surfaces 22 c for the lens barrel at the internal surfaces of the back ends of the coil mounting portions 22 b thereof. The lens barrel 40 includes a lens, has a cylindrical shape, abuts to the internal surfaces of the coil mounting portions 22 b and to the abutment surfaces 22 c for the lens barrel, and is fixed to the lens carrier 38 by making use of an adhesive material.

As best shown in FIG. 4, the magnets 24 includes four rectangular magnetic pieces 24 a, 24 b, 24 c and 24 d. Two magnetic pieces 24 a and 24 b are arranged adjoining along the upward-and-downward direction each other and are fixed to the internal surface of the left side wall 18 a of the yoke 18. The other two magnetic pieces 24 c and 24 d are also arranged adjoining along the upward-and-downward direction each other and are fixed to the internal surface of the right side wall 18 b of the yoke 18 in a manner to be aligned with the magnetic pieces 24 a and 24 b with respect to the upward-and-downward direction. Each of the magnetic pieces 24 a, 24 b, 24 c and 24 d is magnetized so that the outer surface and the inner surface thereof have the different magnetic polarities. Further, each adjoining inner surface and each opposing inner surface of the magnetic pieces 24 a, 24 b, 24 c and 24 d exhibits different magnetic pole each other. For example, if the inner surface of the magnetic piece 24 a is the N-pole, the inner surfaces of the magnetic pieces 24 b and 24 c are the S-pole while the inner surface of the magnetic piece 24 d is the N-pole. It is possible that the magnetic pieces 24 a and 24 b, as well as the magnetic pieces 24 c and 24 d, can be integrally formed, respectively. In that case, the magnetic pieces can be magnetized so that the inner surface of the magnetic piece 24 a (24 c) and the inner surface of the magnetic piece 24 b (24 d) exhibit different magnetic polarities.

As shown in FIG. 6, the each coil mounting portion 22 b of the main body 22 of the lens carrier is formed with two positioning projections 22 d projecting outwardly in a manner that they are aligned each other in the forward-and-backward direction.

The each coil 26 is formed to have a shape including two linear parts and semicircular parts connected to the both ends of the each linear part. The coil 26 has an air core for positioning around the positioning projections 22 d and is positioned thereto by fitting around the positioning projections 22 d thereby being fixed to the lens carrier 38 by making use of an adhesive material. The linear parts of the coils 26 are confronted to the magnetic pieces 24 a to 24 d of the magnets 24. Since electric current flows through the linear parts of the each coil 26 in the forward-and-backward direction and magnetic flux is produced toward the leftward-and-rightward direction of the each coil 26; therefore, an electromagnetic force toward the upward-and-downward direction is applied to the lens carrier 38.

A pair of upper leaf springs 28 is provided at both right and left sides. As shown in FIG. 7, each of the upper leaf spring 28 includes a main body side fixing portion 28 a, a lens carrier side fixing portion 28 b and two spring portions 28 c. The main body side fixing portion 28 a is fixed onto the upper end of the magnet 24. The lens carrier side fixing portion 28 b is fixed onto the upper end of the coil mounting portion 22 b of the main body 22 of the lens carrier. The spring portion 28 c is formed as a wire shape with two bent portions and connects the main body side fixing portion 28 a with the lens carrier side fixing portion 28 b so as to exert an elastic force. The upper leaf springs 28, as a whole structure, include four spring portions 28 c, thus the lens carrier 38 is supported at four perimeter places thereof. The upper leaf springs 28 are attached to the both lateral sides of the lens carrier 38 in a manner that surface of each upper leaf spring 28 is oriented orthogonal to the optical axis direction and they support the lens carrier 38 in a manner to freely move in the optical axis direction of the lens barrel 40 with respect to the lens driving device housing 34.

The lower leaf springs 30, as a whole structure, are divided into two parts in the forward-and-backward direction, and each lower leaf spring 30 has two spring members at the lateral ends thereof. The each lower leaf spring 30, as shown in FIG. 8, has two main body side fixing portions 30 a, a lens carrier side fixing portion 30 b and two spring portions 30 c. The each main body side fixing portion 30 a is fixed on to the upper end of the lower member 16. The lens carrier side fixing portion 30 b is fixed on the bottom portion 22 a of the main body 22 of the lens carrier. The each spring portion 30 c is formed as a wire shape with two bent portions and connects the main body side fixing portion 30 a with the lens carrier side fixing portion 30 b so as to exert an elastic force. The lower leaf springs 30, as a whole structure, include four spring portions 30 c, thus the lens carrier 38 is supported at four perimeter places thereof. The lower leaf springs 30 are attached to the both front and back sides and the both lateral sides of the lens carrier 38 in a manner that surface of each lower leaf spring 30 is oriented orthogonal to the optical axis direction and they support the lens carrier 38 in a manner to freely move in the optical axis direction of the lens barrel 40 with respect to the lens driving device housing 34.

Further, the lower leaf springs 30 are used as electro conductive members. As shown in FIG. 8, the ends 26 a of the above-mentioned coils 26 are connected to the lens carrier side fixing portions 30 b of the lower leaf springs 30 which are divided each other.

Two terminals 32 are connected to the main body side fixing portions 30 a of the lower leaf springs 30 and are also fixed to the lower member 16 together with the main body side fixing portions 30 a. These terminals 32 extend apart from the center of the lens barrel 40 toward the right direction, for example, and extend downward along the side surface of the lower member. An electric current input to one of the terminals 32 flows through the two coils 26 via one of the lower leaf springs 30 and output from the other one of the terminals 32 via the other one of the lower leaf springs 30. The coils 26 are electrically connected in parallel to the terminals 32.

A photo detecting sensor for receiving light which is passed through the lens barrel 40 via an IR filter is arranged below the lower member 16 so as to form a camera device.

In the camera device, the light incident to the prism 36 from an imaging target turns at right angle due to the effect of the prism 36 and is concentrated by the lens barrel 40 onto the photo detecting sensor so as to be detected thereby. A controller which is provided in the camera calculates a movement amount of the lens barrel 40 for focusing on the imaging target. The controller controls an electric voltage to be applied to the terminals 32 in a manner the voltage corresponds to the movement amount of the lens. When electric current flows through the coils 26 via the terminals 32 and the lower leaf springs 30, a magnetic flux from the magnets 24 acts on the coils 26, and an upward and downward moving force is generated in the coils 26. When the electromagnetic force is generated in the coils 26, the lens carrier 38 together with the lens barrel 40 moves against the counterforce of the upper leaf springs 28 and the lower leaf springs 30, thus the lens is focused on the imaging target.

As shown in the above embodiment, since there are not any obstacles obstructing the lens barrel 40 to be inserted into the lens carrier 38 in the front side thereof, it is easy to insert the lens barrel 40 into the lens carrier 38. However, the present invention is not limited to the above example. It can also be possible to form the opening 38 a of the lens carrier 38 in a manner that the lens barrel 40 can be inserted from one of the lateral sides of the lens carrier 38 or the back side of the lens carrier 38. Further, the present invention is not limited to the examples in which the lens barrel 40 is inserted into the lens carrier 38 along the direction orthogonal to the optical axis direction of the lens barrel 40. It can also be possible to insert the lens barrel 40 thereto along any direction which intersects the optical axis direction of the lens barrel 40 at any angle; e.g. the lens barrel 40 can be inserted into the lens carrier 38 from a diagonal direction with respect to the optical axis direction. Further, in the above embodiment, the prism 36; i.e. the optical component forming an optical system which folds the optical axis is arranged on the optical axis direction. However, the present invention can be applied to other embodiments which do not include any optical component such as the one described above. 

What is claimed is:
 1. A lens driving device comprising: a lens carrier for fixing a lens barrel to the inside thereof; a driving unit for moving the lens carrier along the optical axis direction of the lens barrel; and an upper leaf spring and a lower leaf spring attached to the lens carrier in a manner that a surface of the each upper leaf spring and lower leaf spring is oriented orthogonal to the optical axis direction at an upper part and a lower part of the lens carrier and so that the lens carrier is supported so as to move freely in the optical axis direction of the lens barrel; wherein the lens carrier has an opening through which the lens barrel can be inserted from the direction intersecting the optical axis direction of the lens barrel.
 2. The lens driving device according to claim 1, wherein the driving unit has coils and magnets; wherein the coils are arranged on the both sides of the lens carrier around the optical axis of the lens barrel.
 3. The lens driving device according to claim 2, wherein the coils on the both sides of the lens carrier are electrically connected in parallel with respect to each other.
 4. The lens driving device according to claim 2, wherein conducting members for supplying electricity to the coils are provided on one side of the lens carrier in the optical axis direction of the lens barrel.
 5. The lens driving device according to claim 4, wherein terminals connected to the conducting members are arranged on one side apart from the center of the lens barrel.
 6. The lens driving device according to claim 2, wherein the lens driving device further includes a yoke for supporting the magnets; wherein the yoke surrounds the lens carrier except the opening thereof.
 7. The lens driving device according to claim 6, wherein the magnets are fixed to the both sides of the yoke around the optical axis of the lens barrel in a manner to face toward the coils.
 8. The lens driving device according to claim 7, wherein the magnets are arranged facing toward each other in a manner that their magnetic poles of facing sides thereof are different.
 9. The lens driving device according to claim 1, wherein the lens carrier includes a main body made of resin and a reinforcement member made of metal; and wherein the main body is reinforced with respect to a direction intersecting the optical axis direction of the lens barrel by means of the reinforcement member.
 10. The lens driving device according to claim 2, wherein the lens carrier includes a main body made of resin and a reinforcement member made of metal; and wherein the main body is reinforced with respect to a direction intersecting the optical axis direction of the lens barrel by means of the reinforcement member.
 11. The lens driving device according to claim 6, wherein the lens carrier includes a main body made of resin and a reinforcement member made of metal; and wherein the main body is reinforced with respect to a direction intersecting the optical axis direction of the lens barrel by means of the reinforcement member.
 12. The lens driving device according to claim 1, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 13. The lens driving device according to claim 2, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 14. The lens driving device according to claim 6, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 15. The lens driving device according to claim 9, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 16. The lens driving device according to claim 10, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 17. The lens driving device according to claim 11, wherein an optical component for forming an optical system which folds the optical axis is arranged on the optical axis direction of the lens carrier.
 18. A camera device comprising: a lens driving device including: a lens carrier for fixing a lens barrel to the inside thereof; a driving unit for moving the lens carrier along the optical axis direction of the lens barrel; and an upper leaf spring and a lower leaf spring attached to the lens carrier in a manner that a surface of the each upper leaf spring and lower leaf spring is oriented orthogonal to the optical axis direction at an upper part and a lower part of the lens carrier and so that the lens carrier is supported so as to move freely in the optical axis direction of the lens barrel; wherein the lens carrier has an opening through which the lens barrel can be inserted from the direction intersecting the optical axis direction of the lens barrel; and a photo detecting sensor receiving light passed through the lens barrel.
 19. An electronic apparatus being equipped with a camera device including: a lens driving device including: a lens carrier for fixing a lens barrel to the inside thereof; a driving unit for moving the lens carrier along the optical axis direction of the lens barrel; and an upper leaf spring and a lower leaf spring attached to the lens carrier in a manner that a surface of the each upper leaf spring and lower leaf spring is oriented orthogonal to the optical axis direction at an upper part and a lower part of the lens carrier and so that the lens carrier is supported so as to move freely in the optical axis direction of the lens barrel; wherein the lens carrier has an opening through which the lens barrel can be inserted from the direction intersecting the optical axis direction of the lens barrel; and a photo detecting sensor receiving light passed through the lens barrel. 